1. Field of the Invention
It is known that the dyeing properties of pigments in various binders can be improved by admixing dyes containing acid groups.
2. Discussion of the Background
For example, German Published Application DAS No. 2,012,153 discloses pigment mixtures which consist of two or more dyes and in which some of the dyes contain polar groups, such as carboxyl, sulfo, carbamyl or sulfamyl groups. The amount of these acidic dyes can be from 0.5 to 20, preferably from 1 to 5, mol %.
German Published Application DAS No. 2,135,468 discloses pigment formulations consisting of coupling products of diazotized anilines and acetoacetylamides, which contain a water-soluble dye based on the coupling product. The amount of the soluble dye can be from 0.1 to 20% by weight, based on the formulation.
German Published Application DAS No. 2,012,152 describes a process for the preparation of diazo pigment mixtures, in which tetrazotized 3,3'-dichloro-4,4'-diaminodiphenyl is coupled with a mixture in a molar ratio of 1:2, the mixture containing one or two different non-polar coupling components of the acetoacetarylide or 1-arylpyrazol-5-one series and one or two different polar coupling components from these series. The polar components carry one or two carboxyl and/or sulfo groups. The amount of the polar coupling components is from 0.5 to 20, preferably from 1 to 5, mol %.
German Published Application DAS No. 2,122,521 discloses modified diarylide pigments which contain not only the pigment based on 4,4'-diaminodiphenyl with acetoacetarylide, 1-phenyl-3-methylpyrazol-5-one or 2-hydroxynaphthalene-3-carboxanilide, but also up to 25% by weight of a water-soluble dye based on the same compounds.
Furthermore, EP-B No. 12 944 describes monoazo pigment mixtures which are obtained by coupling diazotized anilines to acetoacetarylamides, more than one diazo and/or coupling component being used, and from 0.1 to 20 mol % of the diazo and/or coupling components containing acidic groups and the reactive acidic groups in the coupling product being reacted with quaternary cationic compounds.